Study On The Biological Characteristics And Population Dynamics After Diapause In Lygus Pratensis(L.)

Lygus pratensis(L.)is the dominant species of bug pests in Xinjiang,that seriously affects the production and economic value of cotton and fruit trees.At present,the research on this insect mainly focuses on feeding,host,occurrence regularity and control technology.The relationship between body color and diapause,biological characteristics after diapause and population dynamics before and after diapause are rarely reported.The study on the biological characteristics after diapause and population dynamics before and after overwintering will not only help to clarify the regulation mechanism of diapause and post-diapause development,but also help to understand the adaptive countermeasures of Lygus pratensis(L.)to the ecological environment,and provide scientific basis for improving and improving the prediction level of Lygus pratensis(L.)population and formulating effective comprehensive management strategies.The results of this study are as follows :1.Dynamic changes of body color and internal reproductive system during diapause of Lygus pratensis(L.)The results showed that the body color changed obviously during overwintering,and the body color changed from grey green to brown,brown red and grey brown.Approximately 90 percent of individuals experienced significant changes in diapause color grade 3 and 4 during wintering,and 10 percent maintained color grade 2.The ovarian changes of adults were also obvious during overwintering.The ovaries of diapause females were transparent,and there was no obvious differentiation of ovarian tubules.The ovarian development was basically in the first stage.After the termination of diapause,the ovaries of females noticeably expanded and a large number of eggs were visible.The body color of adults changed to grade 3 before overwintering,the ovary stopped developing,and the female diapause began.After overwintering,the body color of adult changed from diapause to reproductive type,the ovary began to develop,and the female diapause ended.These results indicated that the color change of overwintering adults was an important morphological index of diapause overwintering.The change of body color before and after overwintering marks the beginning and end of adult diapause.2.Effects of temperature and photoperiod on postdiapause development and reproduction of Lygus pratensis(L.)The results showed that under the treatment of photoperiod L15:D9 and different temperatures(16°C and 24°C),the biological parameters of the diapause adult of Lygus pratensis(L.)were significantly affected.The life span of the diapause adult was shortened,as well as the oviposition period of the female.The total oviposition amount within 30 days was decreased.The longevity,oviposition period and total oviposition amount within 30 days of diapause adults at 16°C were lower than those of diapause adults at 24°C.Under the treatment of temperature 24°C and different photoperiods(L9:D15,L15:D9),photoperiod L15:D9 had a significant effect on the biological parameters of adult Lygus pratensis(L.).After diapause,the longevity of adult Lygus pratensis(L.)shortened,the oviposition period of female Lygus pratensis(L.)shortened,and the total oviposition amount decreased within 30 days.The life span,pre-oviposition period,oviposition period and total oviposition amount within 30 days of diapause and non-diapause adults did not change significantly after photoperiod L9:D15.In conclusion,temperature is the decisive factor affecting the development and reproduction of herbivorous bug after diapause.3.Study on population dynamics and prediction models of Lygus pratensis(L.)before and after diapauseThe results showed that before overwintering,the adults of the autumn generation reached the peak on September 15,and most of the overwintering adults diapaused in soil on October 30,while the nymphs reached the peak on September 20.The overwintering adults stinged on March10,and the first generation of larvae began to appear on April 1.On May 15,the first generation of nymphs reached the peak.In early and middle June,the first generation of nymphs almost all emerged as adults.In late June,the first generation of adults and the second generation of larvae were transferred to cotton fields and cause damage to cottons.